Four Portuguese tourists died and 28 were injured on Sunday when their bus came off the road amid icy conditions in the east of France, local politicians said.

According to Rapporteur Report From, EFE, The vehicle had traveled from Portugal and was heading to Switzerland when it came off the RN79 road_ locally dubbed the "road of death"_ near the town of Charolles in the Saône-et-Loire region.

Speaking to the Creusot-info news outlet, director of the office of that region Marlene Germain said "the bus came off the road just before the Charolles viaduct. The bus carried Portuguese nationals traveling to Switzerland."

The incident occurred at around 4.10am local time (3.10am GMT) and was likely due to the icy conditions caused by low temperatures in the region, local lawmaker Gilbert Payet said.

Germain warned other drivers not to take that route at the moment.

Around 75 firefighters, ambulances and medical response personnel attended the scene to provide assistance to the victims, including a seriously injured 2-year-old child.

The local prosecutor's office is to open an investigation into whether some passengers were not wearing seat-belts after it became clear that several of the injured had been thrown from the vehicle during the crash.

Karine Malara, of the Mâcon prosecutor's office, said an investigation would also be launched to establish the speed at which the bus was traveling.

The two drivers, who were among those lightly injured in the crash, are to face police questioning on that matter.

French interior minister Bruno Le Roux expressed his condolences to the families of the victims.

The local government initially reported that five people had died, but one of the victims who had suffered cardiac arrest was revived.

The RN79 motorway, which traverses the nation east to west, is renowned for being one of the most dangerous roads in France.

In Mar. 2016, a similar accident on that road claimed the lives of 12 Portuguese travelers, including two minors, when their minibus crashed head-on with a truck.